In the past, a number of different methods have been developed for causing conventional optical fibers to emit light. U.S. Pat. Nos. 3,508,589 to B. N. Derick et al and 4,234,907 to M. Daniel disclose methods for causing clad or unclad optical fibers to emit light along the length of the fiber. These methods all involve scratching, abrading, chemically deforming, or otherwise removing or disturbing portions of the cladding of the optical fibers so that a small percentage of light travelling down the length of the fibers is emitted through the deformities in the cladding. Unfortunately, however, with a deformed optical fiber, a far greater intensity of light is scattered in the forward direction of light conductivity at small angles relative to the central longitudinal axis of the fiber. Thus, when light emitting fabrics or light emitting optical fiber lighting fixtures are formed from deformed optical fibers, only a small fraction of light is emitted perpendicular to the outer surface of the fabric or layer of optical fibers. When such fabric is viewed edge on, facing into the forward direction of light conduction, the material will appear to be very bright. Additionally, the material will appear to be of moderate brightness when viewed at perpendicular angles to the outer surface, and will appear very dark when viewed edge on along the forward direction of conduction. Consequently, there is a need for developing an optical fiber capable of providing a better angular distribution of emitted light along the fiber length.
For applications where light emitting devices such as light emitting optical fiber lighting fixtures or fabrics are employed, it is often desirable to transmit light to such devices through a single light pipe. In the past, such light pipes have often involved a cable consisting of a multiplicity of optical fibers. Such cables are not only expensive, but are also difficult to effectively couple to a light utiliziation device without extensive light losses.